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magnetic,dielectric and electrical modulus of Ce^(3+) doped cobalt-magnesium ferrite nanoparticles

Journal of Rare Earths 2024年第2期42卷 373-382,I0005页

作者： n.m.Basfer Hanaa Almaghamsi Departm.n. of Physics Umm AL-Qura UniversityMakkahSaudi Arabia Physics Departm.n. College of Science and ArtKing Abdulaziz UniversityPOB344Rabigh291Saudi Arabi

In this work,the magnetic,dielectric properties and electric modulus of Ce^(3+) substituted cobaltmagnesium(Co_(0.7)mg_(0.3)Ce_(x)Fe_(2-x)O_4)(labeled as CmCF) ferrite nanoparticles were investigated in detail.Saturation magnetization decreases from 50.05 to 34.87 emu/g for further substituting Ce^(3+) ions.meanwhile,coercivity increases from 738.22 Gs for the CmCFO sample to 912.10 Gs for the CmCF2 sample,then decreases m.n.tonically to 762.1 Gs for the CmCF5 sample.The cerium content and particle size play important roles in controlling the magnetization and coercivity of the CmCF nanoparticles.All CmCF nanoferrites are suitable for microwave applications since their high-frequency response ranges from 7.72 to 11.07 GHz.The CmCF nanoferrites' dielectric parameter dispersion exhibits normal behavior.The pristine Co-mg nanoferrite only has ε' value of 28.25,but the nanoferrite mCmF2 has ε' value of365.03,with an enhancing ratio of 1192%.The conduction mechanism of the mCmF nanoferrites was determ.n.d by fitting the σ_(ac) results via the Jonscher power law.At 653 K,large polaron tunnelling is thought to be responsible for this conduction process,which is followed by electron barrier hopping at higher temperatures.Cole-Cole diagrams at different temperatures,assuring the contributions of the grains and their boundaries at lower temperatures(653 K) and only the grains at higher temperatures.Based on our results,the CmCF nanoferrites hold magnetic and semiconducting nature,which can be used in magnetic devices and dielectrics in lower-frequencies or conductors in higher-frequencies.

关键词： nanoferrites Rare earth ions magnetic properties Dielectric parameters Impedance spectroscopy

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EDSUCh:A robust ensemble data summarization method for effective medical diagnosis

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Digital Comm.n.cations and networks 2024年第1期10卷 182-189页

作者： mohiuddin Ahmed A.n.m.Bazlur Rashid School of Science Edith Cowan UniversityPerthAustralia

Identifying rare patterns for medical diagnosis is a challenging task due to heterogeneity and the volume of data.Data summarization can create a concise version of the original data that can be used for effective diagnosis.In this paper,we propose an ensemble summarization method that combines clustering and sampling to create a summary of the original data to ensure the inclusion of rare patterns.To the best of our knowledge,there has been no such technique available to augm.n. the perform.n.e of anomaly detection techniques and simultaneously increase the efficiency of medical diagnosis.The perform.n.e of popular anomaly detection algorithms increases significantly in terms of accuracy and computational complexity when the summaries are used.Therefore,the medical diagnosis becomes more effective,and our experim.n.al results reflect that the combination of the proposed summarization scheme and all underlying algorithms used in this paper outperforms the most popular anomaly detection techniques.

关键词： Data summarization Ensemble medical diagnosis Sampling

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A FLEXIBLE OBJECTIVE-COnSTRAInT APPROACH AnD A nEW ALGORITHm FOR COnSTRUCTInG THE PARETO FROnT OF mULTIOBJECTIVE OPTImIZATIOn PROBLEmS

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Acta mathematica Scientia 2024年第2期44卷 702-720页

作者： n.HOSEInPOOR m.GHAZnAVI Faculty of mathematical Sciences Shahrood University of TechnologyShahroodIran

In this article, a novel scalarization technique, called the improved objective-constraint approach, is introduced to find efficient solutions of a given multiobjective programm.n. problem. The presented scalarized problem extends the objective-constraint problem. It is dem.n.trated that how adding variables to the scalarized problem, can lead to find conditions for (weakly, properly) Pareto optimal solutions. Applying the obtained necessary and sufficient conditions, two algorithms for generating the Pareto front approximation of bi-objective and three-objective programm.n. problems are designed. These algorithms are easy to implem.n. and can achieve an even approximation of (weakly, properly) Pareto optimal solutions. These algorithms can be generalized for optimization problems with more than three criterion functions, too. The effectiveness and capability of the algorithms are dem.n.trated in test problems.

关键词： multiobjective optimization Pareto front scalarization objective-constraint approach proper efficient solution

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Characterization of bright betatron radiation generated by direct laser acceleration of electrons in plasma of near critical density

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matter and Radiation at Extremes 2024年第2期9卷 26-35页

作者： J.Cikhardt m.Gyrdymov S.Zähter P.Ta.a.a.m.m.Günther n.Bukharskii n.Borisenko J.Jacoby X.F.Shen A.Pukhov n.E.Andreev O.n.Rosmej Faculty of Electrical Engineering Czech Technical University in Prague16627 Prague 6Czech Republic Goethe University FrankfurtMax-von-Laue-Straße 160438 Frankfurt am MainGermany GSI Helmholtzzentrum für Schwerionenforschung GmbH Planckstraße 164291 DarmstadtGermany Focused Energy GmbH Im Tiefen See 4564293 DarmstadtGermany national Research nuclear University mEPhI Kashirskoe shosse 31115409 MoscowRussian Federation Lebedev Physical Institute RAS Leninskiy Prospekt 53119991 MoscowRussian Federation Heinrich-Heine-University Düsseldorf Universitätsstrasse 1DüsseldorfGermany Joint Institute for High Temperatures RASIzhorskaya st.13Bldg.2125412 MoscowRussian Federation moscow Institute of Physics and Technology Institutskiy Pereulok 9141700 DolgoprudnyRussia

Directed x-rays produced in the interaction of sub-picosecond laser pulses of moderate relativistic intensity with plasma of near-critical density are investigated. Synchrotron-like (betatron) radiation occurs in the process of direct laser acceleration (DLA) of electrons in a relativisticlaser channel when the electrons undergo transverse betatron oscillations in self-generated quasi-static electric and magnetic fields. In anexperim.n. at the PHELIX laser system, high-current directed beams of DLA electrons with a mean energy ten times higher than the ponderomotive potential and maximum energy up to 100 meV were measured at 10^(19) W/cm^(2)laser intensity. The spectrum of directed x-raysin the range of 5–60 keV was evaluated using two sets of Ross filters placed at 0°and 10°to the laser pulse propagation axis. The differential x-ray absorption method allowed for absolute measurem.n.s of the angular-dependent photon fluence. We report 10^(13) photons/sr withenergies >5 keV measured at 0°to the laser axis and a brilliance of 10^(21) photons s^(−1) mm^(−2) mrad−2(0.1%BW)−1. The angular distributionof the emission has an FWHm of 14°–16°. Thanks to the ultra-high photon fluence, point-like radiation source, and ultra-short emissiontime, DLA-based keV backlighters are promising for various applications in high-energy-density research with kilojoule petawatt-class laserfacilities.

关键词： laser acceleration critical

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Changes in children’s cardiorespiratory fitness and body mass index over the course of the COVID‑19 pandemic:a 34‑m.n.h longitudinal study of 331 primary school children

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World Journal of Pediatrics 2024年第2期20卷 185-188页

作者： Gerald Jarnig Reinhold Kerbl mireille n.m.van Poppel Institute of Hum.n.movem.n. Science Sport and HealthUniversity of GrazMozartgasse 148010 GrazAustria Departm.n. of Pediatrics and Adolescent medicine LKH Hochsteiermark8700 LeobenAustria

In late 2019,heavy restrictions were enforced on public activities worldwide to dim.n.sh the spread of the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)virus[1].These restrictions,which included school closures and strictly limited sports and leisure opportunities,particularly impacted children and adolescents[2].Lifestyle changes in children and adolescents led to reduced physical activity levels[2,3],increased sedentary behavior[3,4],changes in eating habits,and changes in sleep habits[3].

关键词： respiratory acute children

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Inclusion of CoTiO_(3) to ameliorate the re/dehydrogenation properties of the mg–na–Al system

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Journal of magnesium and Alloys 2024年第3期12卷 1215-1226页

作者： n.A.Ali n.Y.Yusnizam.n.A.Sazelee Sami-ullah Rather Haizhen Liu m.Ismail Energy Storage Research Group Faculty of Ocean Engineering TechnologyUniversiti Malaysia Terengganu21030 Kuala NerusTerengganuMalaysia Departm.n. of Chemical and materials Engineering King Abdulaziz UniversityP.O.Box80204Jeddah 21589Saudi Arabia Guangxi novel Battery materials Research Center of Engineering Technology School of Physical Science and TechnologyGuangxi UniversityNanning 530004China State Key Laboratory of Featured metal materials and Life-Cycle Safety for Composite Structures Nanning 530004China

For the first time,the mgH_(2)–naAlH_(4)(ratio 4:1)destabilized system with CoTiO_(3) addition has been explored.The CoTiO_(3)-doped mgH_(2)–naAlH_(4) sample begins to dehydrogenate at 130℃,which is declined by 40℃ compared to the undoped mgH_(2)–naAlH_(4).moreover,the de/rehydrogenation kinetics characteristics of the CoTiO_(3)-doped mgH_(2)–naAlH_(4) were greatly ameliorated.With the inclusion of CoTiO_(3),the mgH_(2)–naAlH_(4) composite absorbed 5.2 wt.%H_(2),higher than undoped mgH_(2)–naAlH_(4).In the context of dehydrogenation,the CoTiO_(3)-doped mgH_(2)–naAlH_(4) sample desorbed 2.6 wt.%H_(2),almost doubled compared to the amount of hydrogen desorbed from the undoped mgH_(2)–naAlH_(4) sample.The activation energy obtained by the Kissinger analysis for mgH_(2) decomposition was significantly lower by 35.9 kJ/mol than the undoped mgH_(2)–naAlH_(4) sample.The reaction mechanism dem.n.trated that new phases of mgCo and AlTi_(3) were generated in situ during the heating process and are likely to play a substantial catalytic function and be useful in ameliorating the de/rehydrogenation properties of the destabilized mgH_(2)–naAlH_(4) system with the inclusion of CoTiO_(3).

关键词： Destabilize system magnesium hydride Sodium a.a.a.e Hydrogen storage Additive.

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Empirical model for fusion cross sections of Ca-induced reactions

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Chinese Physics C 2024年第3期48卷 126-132页

作者： Reddi Rani.L n.Sowmya K.n Sridhar H C.m.n.unatha m.m.Armstrong Arasu Departm.n. of Physics St.Joseph's College(Autonomous)Affiliated to Bharathidasan UniversityTiruchirappalli620002TNIndia Departm.n. of Physics Govt.First.Grade CollegeChikkaballapur-562101KarnatakaIndia Departm.n. of Physics Govt.First.Grade CollegeMalur-563160KarnatakaIndia Departm.n. of Physics Govt.First.Grade CollegeDevanahalli-562110KarnatakaIndia

A new empirical formula for the astrophysical S-factor has been suggested as a function of the Coulomb interaction parameter,center of mass energy,and barrier height.About 22 fusion reactions with ^(40,48)Ca as projectiles were considered for different targets,leading to compound nuclei with atomic and mass numbers varying between 40≤Z≤≤Z≤112 and 88≤A≤27888≤A≤278,respectively.The fusion cross-sections have been estimated using the geometric factor,the Gamow-Sommerfield factor,and the empirical formula for the S-factor.This study's findings showed better agreem.n. with those of available experim.n.s when compared to Wong's formula.The present work leads to a smaller standard deviation value than Wong's formula when used to correlate the experim.n.al data of calcium-induced fusion reactions.Wong's formula provides a good approximation of fusion cross-sections when the center of mass energy is below the fusion barrier when compared to above the fusion barrier.

关键词： fusion cross-sections Wong formula Gamow-Sommerfield-factor Geometric-factor S-factor

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Direct microwave leaching conditions of rare earth elem.n.s in fluorescent wastes

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Journal of Rare Earths 2024年第6期42卷 1165-1174,I0007页

作者： A.Bilen B.Birol m.n.Saridede S.S.Kaplan m.S.Sonmez Departm.n. of metallurgical and materials Engineering Yildiz Technical UniversityIstanbulTurkey Departm.n. of Chemical Engineering and materials Science Stevens Institute of TechnologyNew JereyUSA Departm.n. of metallurgical and materials Engineering Istanbul Technical UniversityIstanbulTurkey

The lum.n.scent phosphor powder in the fluorescent lamp constitutes 2%of the lamp’s weight.It can be m.n.ioned that fluorescent wastes are a crucial raw material to produce rare earth oxides.In the present study,microwave leaching process was conducted to dissolve rare earth elem.n.s yttrium(Y),europium(Eu),and remaining rare earth elem.n.s(REEs)present in the phosphor powder of the fluorescent lamp.and the yields were compared.In the microwave leaching process,the effects of the temperature(80-160℃),acid type(hydrochloric acid(HCl),nitric acid(HnO_(3)),sulphuric acid(H_(2)SO_(4))),acid concentration(0.5-6 mol/L),solid to liquid ratio(0.1:10-0.5:10)and reaction time(5-90 m.n.parameters on leaching efficiencies of varying rare earth elem.n.s and calcium were investigated.The highest yield was obtained in the direct microwave leaching of fluorescent waste with the experim.n.al conditions of 6 mol/L HCl,160℃,0.1:10 solid-to-liquid ratio(S:L),and 90 m.n.Activation energy calculations were made,and kinetic models of the reactions were obtained,and it is observed that Y and Eu dissolution is diffusion-controlled,on the other hand,lanthanum(La),cerium(Ce),and terbium(Tb)were exam.n.d to be chemical reaction controlled.moreover,calcium(Ca)and gadolinium(Gd)seem coherent with the mixed model.Concurrently,mathematical models of all experim.n.al studies are created with the response surface Box-Behnken method and the correlation coefficients of all the models are over 90%.

关键词： Rare earth elem.n.s(REEs) Direct microwave leaching Fluorescent waste Kinetic models Response surface method

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nanomotion of bacteria to determ.n. metabolic profile

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nanotechnology and Precision Engineering 2024年第1期7卷 1-9页

作者： S.n.Pleskova E.V.Lazarenko n.A.Bezrukov R.n.Kriukov A.V.Boryakov m.E.Dokukin S.I.Surodin Research Laboratory of Scanning Probe microscopy Lobachevsky State University of Nizhny NovgorodNizhny Novgorod 603950Russia Departm.n. of nanotechnology and Biotechnology Nizhny Novgorod State Technical University n.a.R.E.AlekseevNizhny Novgorod 603950Russia Sarov Physics and Technology Institute National Research Nuclear University MEPhISarov 607186Russia

In addition to their visible motion such as swimm.n.(e.g.,with the help ofﬂagella),bacteria can also exhibit nanomotion that is detectable only with highly sensitive instrum.n.s,and this study shows that it is possible to detect bacterial nanomotion using an AFm detection system.The results show that the nanomotion characteristics depend on the bacterial strain,and that nanomotion can be used to sense the metabolic activity of bacteria because the oscillations are sensitive to the food preferences of the bacteria and the type of surrounding medium.

关键词： nanomotion Bacteria Cantilever Oscillation Atomic force microscopy metabolism

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Enhancem.n. of coercivity,permeability,and dielectric properties of Co_(0.2)Zn_(0.3)ni_(0.5)Eu_(x)Fe_(2)-xO_(4) ferrites for memory and high frequency devices

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Journal of Rare Earths 2024年第6期42卷 1128-1135,I0005页

作者： I.Sardar m.D.Hossain m.S.Sikder m.n.I.Khan m.R.Rahman Physics Discipline Khulna UniversityKhulna9208Bangladesh Departm.n. of Physics Khulna University of Engineering&TechnologyKhulna9203Bangladesh Departm.n. ofComputer Science and Engineering Northern University of Business&Technology KhulnaKhulna9100Bangladesh material Science Division Atomic Energy CentreDhaka1000Bangladesh

Spinel cubic ferrites have huge applications in me mory and high frequency devices.For the improvem.n. of these modern devices,the magnetic coercivity,permeability,and dielectric properties of a ferrite are the important issues.This article focuses on improving the magnetic coercivity,magnetic permeability,and dielectric properties of Co_(0.2)Zn_(0.3)ni_(0.5)Eu_(x)Fe_(2)-xO_(4) ferrites,where x=0.00,0.06,and 0.10.The X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),field emission scanning electron microscopy(FESEm),energy dispersive X-ray(EDX),vibrating sample magnetometer(VSm),and an impedance analyzer were used to characterize the structural,magnetic,and dielectric properties of the samples.The XRD patterns indicate the formation of spinel cubic structure of the samples with a secondary peak(EuFeO_(3))for Eu doped samples.The densities and porosities of the samples follow an inverse trend,where the doped samples’lattice parameters are increased with the increm.n. of rare earth Eu concentration.The FTIR analysis also proves the spinel cubic phase of the samples.The average grain size of the ferrites is obtained via FESEm images,and it is increased from 121 to 198 nm.VSm analysis confirms that doping of the Eu content also changes other hysteresis loop properties of Co_(0.2)Zn_(0.3)ni_(0.5)Eu_(x)Fe_(2)-xO_(4) ferrites.Particularly,the coercivity of the Eu doped samples is greater than that of the mother alloy(x=0.00).The EDX study shows that there is no impurity contam.n.tion in the ferrites.The permeability and dielectric measurem.n.s show an improved quality factor of the Eu-doped samples with low magnetic and dielectric losses.Frequency dependent resistivity and impedance analysis also show the improved nature.From the observed properties of the samples,all the investigated ferrites might be strong candidates for potential applications in memory devices,magnetic sensors,and high frequency applications.

关键词： Ferrites Raree arths Coercivity Permeability EDX Resistivity

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